LiBS analyzer sample presence detection system and method

• US 9,970,815 B2
• Filed: 04/11/2017
• Issued: 05/15/2018
• Est. Priority Date: 02/26/2015
• Status: Active Grant

• Current Assignee: SciAps, Inc.
• Original Assignee: SciAps, Inc.
• Inventors: Day, David R., Sackett, Donald W.
• Primary Examiner(s): Ahmed, Jamil
• Application Number:
  US15/484,767
• Publication Number:
  US 20170219429A1
• Time in Patent Office: 399 Days
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/443 Emission spectrometry
• CPC Class Codes: G01N 21/718 Laser microanalysis, i.e. with formation of sample plasma
• CPC Class Codes: G01N 2201/06113 Coherent sources; lasers
• CPC Class Codes: G01N 2201/069 Supply of sources

Abstract

A LIBS analyzer and method includes a laser configured to produce a plasma on a sample at a focal point on the sample and a spectrometer responsive to radiation emitted from the plasma and configured to produce an output spectrum. A detector is positioned to detect low intensity pre-firing radiation produced by the laser and reflected off the sample from the focal point. The intensity of the low intensity pre-firing radiation is compared to a predetermined minimum and the laser pump sequence is halted if the intensity of the low intensity pre-firing radiation is less than the predetermined minimum.

Claims

1. A LIBS analysis method comprising:

initiating a laser pump sequence to produce low intensity pre-firing radiation;

analyzing said low intensity pre-firing radiation to determine if a sample is present;

if the analysis reveals the sample is present, continuing the laser pump sequence; and

if the analysis reveals the sample is not present, halting the laser pump sequence.

2. The method of claim 1 in which the intensity of said low intensity pre-firing radiation is compared to a predetermined minimum.

3. The method of claim 1 in which a laser pump sequence includes, at least before the first full laser discharge pump duration, a short pump duration which produces said low intensity pre-firing radiation but not a high intensity laser discharge.

4. The method of claim 3 in which there is a short pump duration before each full laser discharge pump duration in the laser pump sequence.

5. A LIBS analysis method comprising:

firing a laser configured to produce a plasma on a sample at a focal point on the sample;

receiving radiation emitted from the plasma and producing a spectrum;

detecting low intensity pre-firing radiation produced by the laser and reflected off the sample;

comparing the intensity of said low intensity pre-firing radiation to a predetermined minimum and halting laser firing if the intensity of said low intensity pre-firing radiation is less than said predetermined minimum; and

continue firing the laser if the intensity of said low intensity pre-firing radiation is greater than said predetermined minimum.